/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package cn.cloud.all.security.core;

import org.springframework.util.Assert;

import java.io.Serializable;
import java.time.Instant;
import java.util.Collections;
import java.util.Set;

/**
 * An implementation of an {@link AbstractOAuth2Token} representing an OAuth 2.0 Access Token.
 *
 * <p>
 * An access token is a credential that represents an authorization
 * granted by the resource owner to the client.
 * It is primarily used by the client to access protected resources on either a
 * resource server or the authorization server that originally issued the access token.
 *
 * @author Joe Grandja
 * @see <a target="_blank" href="https://tools.ietf.org/html/rfc6749#section-1.4">Section 1.4 Access Token</a>
 * @since 5.0
 */
public class OAuth2AccessToken extends AbstractOAuth2Token {
    private final TokenType tokenType;
    private final Set<String> scopes;

    /**
     * Constructs an {@code OAuth2AccessToken} using the provided parameters.
     *
     * @param tokenType  the token type
     * @param tokenValue the token value
     * @param issuedAt   the time at which the token was issued
     * @param expiresAt  the expiration time on or after which the token MUST NOT be accepted
     */
    public OAuth2AccessToken(TokenType tokenType, String tokenValue, Instant issuedAt, Instant expiresAt) {
        this(tokenType, tokenValue, issuedAt, expiresAt, Collections.emptySet());
    }

    /**
     * Constructs an {@code OAuth2AccessToken} using the provided parameters.
     *
     * @param tokenType  the token type
     * @param tokenValue the token value
     * @param issuedAt   the time at which the token was issued
     * @param expiresAt  the expiration time on or after which the token MUST NOT be accepted
     * @param scopes     the scope(s) associated to the token
     */
    public OAuth2AccessToken(TokenType tokenType, String tokenValue, Instant issuedAt, Instant expiresAt, Set<String> scopes) {
        super(tokenValue, issuedAt, expiresAt);
        Assert.notNull(tokenType, "tokenType cannot be null");
        this.tokenType = tokenType;
        this.scopes = Collections.unmodifiableSet(
                scopes != null ? scopes : Collections.emptySet());
    }

    /**
     * Returns the {@link TokenType token type}.
     *
     * @return the {@link TokenType}
     */
    public TokenType getTokenType() {
        return this.tokenType;
    }

    /**
     * Returns the scope(s) associated to the token.
     *
     * @return the scope(s) associated to the token
     */
    public Set<String> getScopes() {
        return this.scopes;
    }

    /**
     * Access Token Types.
     *
     * @see <a target="_blank" href="https://tools.ietf.org/html/rfc6749#section-7.1">Section 7.1 Access Token Types</a>
     */
    public static final class TokenType implements Serializable {
        private static final long serialVersionUID = SpringSecurityCoreVersion.SERIAL_VERSION_UID;
        public static final TokenType BEARER = new TokenType("Bearer");
        private final String value;

        private TokenType(String value) {
            Assert.hasText(value, "value cannot be empty");
            this.value = value;
        }

        /**
         * Returns the value of the token type.
         *
         * @return the value of the token type
         */
        public String getValue() {
            return this.value;
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (obj == null || this.getClass() != obj.getClass()) {
                return false;
            }
            TokenType that = (TokenType) obj;
            return this.getValue().equalsIgnoreCase(that.getValue());
        }

        @Override
        public int hashCode() {
            return this.getValue().hashCode();
        }
    }
}
